Factors Contributing to Decline in Foodborne Disease Outbreak Reports, United States

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Maho Imanishi, Karunya Manikonda

, Bhavini P. Murthy, and L. Hannah Gould

Author affiliations: Centers for Disease Control and Prevention, Atlanta, Georgia, USA

Abstract

The number of foodborne disease outbreaks reported in the United States declined substantially in 2009, when the surveillance system transitioned from reporting only foodborne disease outbreaks to reporting all enteric disease outbreaks. A 2013 survey found that some outbreaks that would have been previously reported as foodborne are now reported as having other transmission modes.

Thumbnail of Total number of foodborne disease outbreaks and number caused by norovirus and Salmonella spp. as reported to the Foodborne Disease Outbreak Surveillance System, United States, 1998–2012. Data current as of April 22, 2014.

Figure. Total number of foodborne disease outbreaks and number caused by norovirus and Salmonella spp. as reported to the Foodborne Disease Outbreak Surveillance System, United States, 1998–2012. Data current as of April...

Since 1973, the Centers for Disease Control and Prevention (CDC) has collected data on foodborne disease outbreaks submitted by all states, the District of Columbia, and US territories through the Foodborne Disease Outbreak Surveillance System. In 2009, existing foodborne and waterborne disease outbreak surveillance systems were transitioned to an enhanced reporting platform, the National Outbreak Reporting System (NORS), which also collects reports of enteric disease outbreaks transmitted through person-to-person contact, contact with animals, environmental contamination, and indeterminate means (1). A new electronic reporting form and data entry interface were also introduced. In 2009, the number of reported foodborne disease outbreaks declined 32% compared with the mean of the preceding 5 years (2); the number also remained below the pre-2009 average during 2010–2012 (2,3) (Figure). The decline was largely observed among outbreaks attributed to norovirus (Figure), which can be transmitted through many routes: in comparison, the number of outbreaks attributed to Salmonella spp., which is usually transmitted through food, remained relatively constant (1,2).

We considered 3 possible reasons for the decline in the number of reported foodborne disease outbreaks: 1) classification of some outbreaks that previously would have been reported as foodborne as caused by another modeof transmission; 2) technical issues associated with the introduction of the new system; and 3) staffing and resource limitations related to the influenza A(H1N1)pdm09 virus pandemic. Clarification of how these factors might have affected reporting would provide accurate conclusions about trends in foodborne disease outbreaks. In 2013, we conducted a survey to identify possible reasons for the decline in the number of foodborne disease outbreak reports that started in 2009.

At the time of the survey, Dr Imanishi was an Epidemic Intelligence Service Officer with the Division of Foodborne, Waterborne, and Environmental Diseases of the National Center for Emerging and Zoonotic Infectious Diseases, CDC. Her research interests include epidemiology and control of foodborne diseases and zoonoses.

Acknowledgment

We would like to acknowledge state, local, and territorial health departments for contributing data to NORS. We also thank the NORS Foodborne, Waterborne, and Person-to-Person teams as well as the CDC Enteric Diseases Epidemiology Branch.

References

Hall AJ, Wikswo ME, Manikonda K, Roberts VA, Yoder JS, Gould LH. Acute gastroenteritis surveillance through the National Outbreak Reporting System, United States. Emerg Infect Dis. 2013;19:1305–9 . DOI PubMed
Centers for Disease Control and Prevention. Surveillance for foodborne disease outbreaks—United States, 2009–2010. MMWR Morb Mortal Wkly Rep. 2013;62:41–7 .PubMed
Centers for Disease Control and Prevention. Foodborne Outbreak Online Database [cited 2014 Jan 7]. http://wwwn.cdc.gov/foodborneoutbreaks
National Association of County and City Health Officials. Local health department job losses and program cuts: findings from January/February 2010 survey. Washington (DC): National Association of County and City Health Officials; 2012.

Figure

Figure. Total number of foodborne disease outbreaks and number caused by norovirus and Salmonella spp. as reported to the Foodborne Disease Outbreak Surveillance System, United States, 1998–2012. Data current as of...

Table

Table. Number of survey respondents reporting difficulty in distinguishing between foodborne disease outbreaks and outbreaks caused by other modes of transmission in the National Outbreak Reporting System, United States, 2013

Suggested citation for this article: Imanishi M, Manikonda K, Murthy BP, Gould LH. Factors contributing to decline in foodborne disease outbreak reports, United States. Emerg Infect Dis [Internet]. 2014 Sep [date cited]. http://dx.doi.org/10.3201/eid2009.140044

DOI: 10.3201/eid2009.140044